Bhagavad-gītā 9.32

It is clearly declared here by the Supreme Lord that in devotional service there is no distinction between the lower or higher classes of people. In the material conception of life, there are such divisions, but for a person engaged in transcendental devotional service to the Lord, there are not. Everyone is eligible for the supreme destination. In the Śrīmad-Bhāgavatam it is stated that even the lowest, who are called caṇḍālas (dog-eaters), can be elevated by association with a pure devotee. Therefore devotional service and guidance of a pure devotee are so strong that there is no discrimination between the lower and higher classes of men; anyone can take to it. The most simple man taking center of the pure devotee can be purified by proper guidance. According to the different modes of material nature, men are classified in the mode of goodness (brāhmaṇas), the mode of passion (kṣatriyas, or administrators), the mixed modes of passion and ignorance (vaiśyas, or merchants), and the mode of ignorance (śūdras, or workers). Those lower than them are called caṇḍālas, and they are born in sinful families. Generally, those who are born in sinful families are not accepted by the higher classes. But the process of devotional service and the pure devotee of the Supreme God are so strong that all the lower classes can attain the highest perfection of life. This is possible only when one takes center of Kṛṣṇa. One has to take center completely of Kṛṣṇa. Then one can become much greater than great jñānīs and yogīs.